Mechanical fastening nets and methods of making the same

ABSTRACT

A method of making a mechanical fastening net. The method includes providing a net having strands of polymer and open areas between the strands of polymer and molding a portion of the polymer in the strands of the net into upstanding posts to form the mechanical fastening net. A mechanical fastening net that includes a polymeric backing, a plurality of openings in the polymeric backing, and upstanding posts on at least one of the first or second major surface of the polymeric backing is also disclosed. The polymeric backing has a range of thicknesses ranging from minimum to maximum thickness, and for at least a portion of the polymeric backing, the minimum thickness of the polymeric backing is where it abuts one of the openings.

BACKGROUND

Hook and loop fastening systems, where the hook member typicallyincludes a plurality of closely spaced upstanding projections withloop-engaging heads, and the loop member typically includes a pluralityof woven, nonwoven, or knitted loops, are useful for providingreleasable attachment in numerous applications. For example, hook andloop fastening systems are widely used in wearable disposable absorbentarticles to fasten such articles around the body of a person. In typicalconfigurations, a hook strip or patch on a fastening tab attached to therear waist portion of a diaper or incontinence garment, for example, canfasten to a landing zone of loop material on the front waist region, orthe hook strip or patch can fasten to the backsheet (e.g., nonwovenbacksheet) of the diaper or incontinence garment in the front waistregion. Hook and loop fasteners are also useful for disposable articlessuch as sanitary napkins. A sanitary napkin typically includes a backsheet that is intended to be placed adjacent to the wearer'sundergarment. The back sheet may comprise hook fastener elements tosecurely attach the sanitary napkin to the undergarment, whichmechanically engages with the hook fastener elements.

Some hook members have been made with openings in the backing from whichthe hooks project. See, e.g., U.S. Pat. No. 4,001,366 (Brumlik) and U.S.Pat. No. 7,407,496 (Peterson), U.S. Pat. Appl. Pub. No. 2002/0112325(Keohan et al.), and Int. Pat. Appl. Pub. Nos. WO 2005/122818 (Ausen etal.) and WO 1994/02091 (Hamilton).

SUMMARY

In one aspect, the present disclosure provides a method of making amechanical fastening net. The method includes providing a net havingstrands of polymer and open areas between the strands of polymer, andmolding a portion of the polymer in the strands of the net intoupstanding posts to form the mechanical fastening net. It should beunderstood that the net and the upstanding posts are not formedsimultaneously.

In another aspect, the present disclosure provides a mechanicalfastening net. The mechanical fastening net has a polymeric backing withfirst and second major surfaces, a plurality of openings in thepolymeric backing extending between the first and second major surfaces,and upstanding posts on at least one of the first or second majorsurface of the polymeric backing. The openings each have a series ofareas through the openings from the first to second major surfacesranging from minimum to maximum areas, and for at least a portion of theopenings, the minimum area is not at either the first or second majorsurface.

In another aspect, the present disclosure provides a mechanicalfastening net. The mechanical fastening net includes a polymeric backinghaving first and second major surfaces, a plurality of openings in thepolymeric backing extending between the first and second major surfaces,and upstanding posts on at least one of the first or second majorsurface of the polymeric backing. Between the openings, the polymericbacking has a range of thicknesses ranging from minimum to maximumthickness, and for at least a portion of the polymeric backing, theminimum thickness of the polymeric backing is where it abuts one of theopenings.

In the mechanical fastening nets of the foregoing aspects, theupstanding posts are generally molded from the polymer forming thepolymeric backing.

In another aspect, the present disclosure provides a laminate comprisingthe mechanical fastening net according to and/or made according to anyof the above aspects joined to a carrier.

The mechanical fastening nets according to and/or made according to anyof the above aspects may be useful, for example, in laminates, strips,or patches that have a unique and attractive appearance. The openingscan provide breathability and flexibility to the mechanical fastener,which may enhance the comfort of the wearer, for example, of anabsorbent article comprising the mechanical fastener made by the methoddisclosed herein. The mechanical fastener also is typically able tocover a relatively larger area with a relatively smaller amount ofmaterial, which may lower its cost relative to a mechanical fastener notprovided with openings. Also, because of the large area that may becovered by the mechanical fastener in an absorbent article, themechanical fastener may provide performance enhancement, for example, byresist shifting forces such as torsional or rotational forces caused bymovement of the wearer of the absorbent article. For example, in use,fitting an absorbent article such as a diaper about the wearer usuallyrequires the front and back waist portions of the diaper to overlap eachother. As the diaper is worn the movements of the wearer tend to causethe overlapping front and back waist portions to shift position relativeto each other. Unless such shifting is limited, the fit and containmentcharacteristics of the diaper may be degraded as the diaper is worn. Themechanical fastener made according to the present disclosure may provideimproved fit and closure stability by resisting such shifting because ofits relatively larger area and flexibility. The amount of open area inthe mechanical fastening net may be adjusted based upon, for example,the desired appearance, weight, or cost in the final product. The methoddisclosed herein allows openings to be provided in the mechanicalfastener without wasteful material loss.

In this application, terms such as “a”, “an” and “the” are not intendedto refer to only a singular entity, but include the general class ofwhich a specific example may be used for illustration. The terms “a”,“an”, and “the” are used interchangeably with the term “at least one”.The phrases “at least one of” and “comprises at least one of” followedby a list refers to any one of the items in the list and any combinationof two or more items in the list. All numerical ranges are inclusive oftheir endpoints and non-integral values between the endpoints unlessotherwise stated.

The terms “first” and “second” are used in this disclosure. It will beunderstood that, unless otherwise noted, those terms are used in theirrelative sense only. In particular, in some embodiments certaincomponents may be present in interchangeable and/or identical multiples(e.g., pairs). For these components, the designation of “first” and“second” may be applied to the components merely as a matter ofconvenience in the description of one or more of the embodiments.

The terms “multiple” and “a plurality” refer to more than one.

BRIEF DESCRIPTION OF THE DRAWINGS

The disclosure may be more completely understood in consideration of thefollowing detailed description of various embodiments of the disclosurein connection with the accompanying drawings, in which:

FIG. 1 is a schematic view of an embodiment of an apparatus useful forthe method of making a mechanical fastening net according to the presentdisclosure;

FIG. 2 is a cross-section view of an embodiment of the mechanicalfastening net disclosed herein taken along section lines 2-2 in FIG. 1;

FIG. 3 is an exploded perspective view of an embodiment of a set ofextrusion die elements suitable for use in the apparatus of FIG. 1,including a plurality of shims, a set of end blocks, bolts forassembling the components, and inlet fittings for the materials to beextruded;

FIG. 4 is a plan view of one of the shims of FIG. 3;

FIG. 5 is a plan view of another one of the shims of FIG. 3;

FIG. 6 is a plan view of yet another one of the shims of FIG. 3;

FIG. 7 is a schematic perspective view of a portion of the extrusion dieof FIG. 3, supplied with polymeric material and forming a net;

FIG. 7 a is a schematic perspective view of another embodiment of anapparatus useful for the method of making a mechanical fastening netaccording to the present disclosure having a different arrangement ofthe extrusion die relative to the nip than the apparatus shown in FIG.1;

FIG. 7 b is a schematic perspective view of an alternate nip roll;

FIG. 8 is a close up front view of the dispensing surface of anextrusion die used in certain of the Examples;

FIG. 9 is an optical digital photo of the mechanical fastening net ofExample 1;

FIG. 10 is a scanning electron digital photomicrograph of thecross-section of one of the holes of the mechanical fastening net shownin FIG. 9;

FIG. 11 is a plan view of an example of a shim for making nettingextruded from a single cavity useful for some embodiments of the methodof making a mechanical fastening net according to the presentdisclosure;

FIG. 12 is a plan view of an example of a shim for making netting usefulin conjunction with the shim of FIG. 11;

FIG. 13 is a plan view of an example of a spacer shim for making nettinguseful in conjunction with the shims of FIG. 11 and FIG. 12;

FIG. 14 is a detail perspective view of a plurality of shims formed fromthe shims of FIGS. 11, 12, and 13;

FIG. 15 is a detail perspective view of the plurality of shims of FIG.14, seen from the reverse angle, with one of the shims removed fromvisual clarity;

FIG. 16 is an optical digital photo of the polymeric net startingmaterial for Example 2;

FIG. 17 is an optical digital photo showing a top view of the mechanicalfastening net of Example 2;

FIG. 18 is an optical digital photo showing a cross-sectional view ofthe mechanical fastening net of Example 2; and

FIG. 19 is an optical digital photo showing a top view of the mechanicalfastening net of Example 2 at higher magnification than in FIG. 17.

DETAILED DESCRIPTION

FIG. 1 illustrates an embodiment of the method according to the presentdisclosure. In this embodiment, the method includes extruding the net.Referring to FIG. 1, exemplary apparatus 20 useful for carrying out themethod disclosed herein is shown. Apparatus 20 has die 22 extruding apolymeric net 24 comprising first strands 26 and second strands 28. Inthe illustrated embodiment, first and second strands 26 and 28 arejoined together at bond regions 30. As shown, polymeric netting 24 isextruded vertically, into nip 40. Vertical extrusion, that is, in thedirection of gravity, may be useful, for example, for allowing collinearstrands to collide with each other before becoming out of alignment witheach other. Nip 40 includes backup roll 42, and a forming surface, whichin the illustrated embodiment is forming roll 44. Forming roll 44includes cavities 46 having the inverse shape of upstanding posts. Insome embodiments, backup roll 42 is a smooth, chrome-plated steel rolland forming roll 44 is a silicone rubber roll. Forming roll 44 may alsobe a metal roll. In some embodiments, both backup roll 42 and formingroll 44 can be temperature controlled with, for example, internal waterflow. In some embodiments, for example the one depicted here, polymericnet 24 passes directly into nip 40, and nip 40 is a quench nip. However,this is not considered necessary, and the extrusion of the netting andthe entry into the nip need not be immediately sequential. After passingthrough nip 40, the polymeric net 24 has been transformed into amechanical fastening net. In some embodiments, it may be advantageous toallow the mechanical fastening net to remain wrapped around forming roll44 for at least a portion of its circumference.

An embodiment of the mechanical fastening net according to the presentdisclosure is also shown in FIG. 1. Mechanical fastening net includes apolymer backing 50 with a first major surface 52 on the side towards theviewer, and second major surface 54 on the side opposite from theviewer. The first major surface 52 is provided with upstanding posts,which are not shown in FIG. 1 for visual clarity. Numerous openings 56pass through polymeric backing 50 from first major surface 52 to secondmajor surface 54. In the illustrated embodiment, openings 56 havewell-formed, smooth edges 58. Further, in the illustrated embodiment,openings 56 taper inwards from both first major surface 52 and secondmajor surface 54 so that opening 56 has a minimum area 60 somewhere inthe interior of polymeric backing 50. These features of openings 56 canbe better appreciated in FIG. 2, which is a cross-section view ofpolymeric backing 50 taken along section lines 2-2 in FIG. 1. The pointwhere opening 56 tapers down to a minimum area 60 is shown to be in theinterior of polymeric backing 50. It should be understood that thepolymeric backing 50 is also at a minimum thickness at this point.Upstanding posts 62 on the polymer backing 50 are also shown in FIG. 2.

In embodiments, including the illustrated embodiment, wherein theopenings each have a series of areas from the first to second majorsurfaces ranging from minimum to maximum areas, the position of theminimum area of the opening is typically influenced, for example, by themethod of making the mechanical fastening net. For example, when anextruded, molten polymer net 24 is fed directly into nip 40, which is aquench nip, the outer surfaces of the first and second strands 26 and 28tend to be cooled more quickly than the interior. This can typicallyoccur after extruding a net without letting it completely solidify (insome embodiments, cool to room temperature). As a result, as the polymernet 24 is pressed in the nip, the interior of the strands tend to bulgeoutward more than the outer surfaces. In the resulting polymer backing50 in the mechanical fastening net, for at least a portion of theopenings 56, the minimum area 60 of the openings is not at either thefirst or second major surface 52 or 54. Further explanation andillustrations of this phenomenon can be found in co-pending applicationhaving U.S. Ser. No. 61/615,676, filed Mar. 26, 2012, the disclosure ofwhich is incorporated herein by reference. It has been observed that thetemperature of the molten polymer, the temperature of the quench, andthe thickness of the molten polymer affect the size of the openings.Higher melt temperature allows more movement of polymer in the nip whichtends to create smaller opening sizes. Low temperature quenching hasbeen shown to limit the amount of polymer movement which creates largeropening sizes.

In embodiments of the method according to the present disclosure thatinclude extruding the net, a variety of methods of extruding a net maybe useful. For example, the apparatus described in U.S. Pat. No.4,038,008 (Larsen) may be useful.

In some embodiments, extruding the net includes providing an extrusiondie having a plurality of shims positioned adjacent to one another, theshims together defining a first cavity and a second cavity, theextrusion die having a plurality of first dispensing orifices in fluidcommunication with the first cavity and having a plurality of seconddispensing orifices connected to the second cavity, such that the firstand second dispensing orifices are alternated. First polymeric strandsare dispense from the first dispensing orifices at a first strand speedwhile simultaneously second polymeric strands are dispensed from thesecond dispensing orifices at a second strand speed, wherein the firststrand speed is at least 2 times the second strand speed. In someembodiments, the first strand speed is in a range from 2 to 6 or from 2to 4 times the second strand speed. In some embodiments, the firstcavity of the extrusion die is supplied with a first polymer at a firstpressure so as to dispense the first polymer from the first array at afirst strand speed, the second cavity of the extrusion die is suppliedwith a second polymer at a second pressure so as to dispense the secondpolymer from the second array at a second strand speed, wherein thefirst strand speed is at least 2 (in some embodiments, 2 to 6, or 2 to4) times the second strand speed. In some embodiments, the plurality ofshims comprises a plurality of a repeating sequence of shims thatincludes a shim that provides a passageway between the first cavity andat least one of the first dispensing orifices and a shim that provides apassageway between the second cavity and the at least one of the seconddispensing orifices.

For some of these embodiments, a useful extrusion die is illustrated inFIG. 3. In FIG. 3, extrusion die 22 includes plurality of shims 70. Insome embodiments of extrusion dies described herein, there will be alarge number of very thin shims 70 (typically several thousand shims; insome embodiments, at least 1000, 2000, 3000, 4000, 5000, 6000, 7000,8000, 9000, or even at least 10,000), of diverse types (e.g., shims 70a, 70 b, and 70 c), compressed between two end blocks (e.g., 74 a and 74b). Conveniently, fasteners (e.g., through bolts 76 threaded onto nuts78) are used to assemble the components for extrusion die 22 by passingthrough holes 79. Inlet fittings 80 a and 80 b are provided on endblocks 74 a and 74 b respectively to introduce the materials to beextruded into extrusion die 22. In some embodiments, inlet fittings 80 aand 80 b are connected to melt trains of conventional type. In someembodiments, cartridge heaters 82 are inserted into receptacles 84 inextrusion die 22 to maintain the materials to be extruded at a desirabletemperature while in the die. The ordinary artisan may perceivealternatives for assembling the extrusion die other than that shown inthe illustrated embodiment. In some embodiments, the assembled shims(conveniently bolted between the end blocks) further comprise a manifoldbody (not shown) for supporting the shims. The manifold body has atleast one (or more (e.g., two or three, four, or more)) manifoldtherein, the manifold having an outlet. An expansion seal (e.g., made ofcopper or alloys thereof) is disposed so as to seal the manifold bodyand the shims, such that the expansion seal defines a portion of atleast one of the cavities (in some embodiments, a portion of both thefirst and second cavities), and such that the expansion seal allows aconduit between the manifold and the cavity.

Referring now to FIG. 4, a plan view of shim 70 a from FIG. 3 isillustrated. Shim 70 a has first aperture 90 a and second aperture 90 b.When extrusion die 22 is assembled, first apertures 90 a in shims 70together define at least a portion of first cavity 92 a. Similarly,second apertures 90 b in shims 70 together define at least a portion ofsecond cavity 92 b. Material to be extruded conveniently enters firstcavity 92 a via inlet port 80 a, while material to be extrudedconveniently enters second cavity 92 b via inlet port 80 b. Shim 70 ahas duct 94 ending in first dispensing orifice 96 a in a dispensingsurface 97. Shim 70 a further has passageway 98 a affording a conduitbetween first cavity 92 a and duct 94. The dimensions of duct 94, andespecially first dispensing orifice 96 a at its end, are constrained bythe dimensions desired in the polymer strands extruded from them. Sincethe strand speed of the strand emerging from first dispensing orifice 96a is also of significance, manipulation of the pressure in cavity 92 aand the dimensions of passageway 98 a can be used to set the desiredstrand speed.

Referring now to FIG. 5, shim 70 b is a reflection of shim 70 a, havinga passageway instead affording a conduit between second cavity 92 b andsecond dispensing orifice 96 b.

Referring now to FIG. 6, a plan view of shim 70 c from FIG. 3 isillustrated Shim 70 c has no passageway between either of first orsecond cavities 92 a and 92 b, respectively, and no duct opening ontodispensing surface 97.

The shims can have thicknesses in the range from 50 micrometers to 500micrometers, although thicknesses outside of this range may also beuseful. The shims are typically metal, for example, stainless steel. Toreduce size changes with heat cycling, metal shims are typicallyheat-treated. The shims can be made by conventional techniques,including wire electrical discharge and laser machining. Often, aplurality of shims are made at the same time by stacking a plurality ofsheets and then creating the desired openings simultaneously.Variability of the flow channels is preferably within 0.025 mm (1 mil),more preferably, within 0.013 mm (0.5 mil). The shims are tightlycompressed to prevent gaps between the shims and polymer leakage. Forexample, 12 mm (0.5 inch) diameter bolts are typically used andtightened, at the extrusion temperature, to their recommended torquerating. Also, the shims are aligned to provide uniform extrusion out theextrusion orifice, as misalignment can lead to strands extruding at anangle out of the die which inhibits desired bonding of the net. To aidin alignment, an alignment key can be cut into the shims. Also, avibrating table can be useful to provide a smooth surface alignment ofthe extrusion tip.

In some embodiments, the shims are assembled according to a plan thatprovides a repeating sequence of shims of diverse types, such as shims70 a, 70 b, and 70 c, illustrated in FIGS. 4, 5, and 6. The repeatingsequence can have two or more shims per repeat. For example, a two-shimrepeating sequence could comprise a shim that provides a passagewaybetween the first cavity and a first dispensing orifice (e.g., shim 70a) and a shim that provides a passageway between the second cavity and asecond dispensing orifice (e.g., shim 70 b). In another example, afour-shim repeating sequence could comprise a shim that provides apassageway between the first cavity and a dispensing surface (e.g., shim70 a), a spacer shim (e.g., shim 70 c), a shim that provides apassageway between the second cavity and a dispensing orifice (e.g.,shim 70 b), and a spacer shim (e.g., shim 70 c).

When the shims are assembled, the cross-sectional shapes of thepassageways may be, for example, square or rectangular. The shape of thepassageways within, for example, a repeating sequence of shims, may beidentical or different. For example, in some embodiments, the shims thatprovide a passageway between the first cavity and a first dispensingorifice might have a flow restriction compared to the shims that providea conduit between the second cavity and a second dispensing orifice. Thewidth of the distal opening within, for example, a repeating sequence ofshims, may be identical or different. For example, the portion of thedistal opening provided by the shims that provide a conduit between thefirst cavity and a first dispensing orifice could be narrower than theportion of the distal opening provided by the shims that provide aconduit between the second cavity and a second dispensing orifice.Furthermore, the shape of a dispensing orifice within, for example, arepeating sequence of shims, may be identical or different. For example,a 4-shim repeating sequence could be employed having a shim thatprovides a passageway between the first cavity and first dispensingorifice, a spacer shim, a shim that provides a passageway between thesecond cavity and a second dispensing orifice, and a spacer shim,wherein the shims that provide a passageway between the second cavityand a second dispensing orifice have a narrowed passage displaced fromboth edges of the distal opening, relative to the shims that provide apassageway between the first cavity and the first dispensing orifice.Also, each of the first and second dispensing orifices can have adifferent cross sectional area.

Typically, the first fluid passageways have greater fluid restrictionthan the second fluid passageways. Typically, the fluid passageways havethicknesses in a range from 50 micrometers to 750 micrometers, andlengths less than 5 mm (with generally a preference for smaller lengthsfor decreasingly smaller passageway thicknesses), although thicknessesand lengths outside of these ranges may also be useful. For largediameter fluid passageways several smaller thickness shims may bestacked together, or single shims of the desired passageway width may beused.

In some embodiments of the dies useful for extruding a polymer, each ofthe first and the second dispensing orifices have a width, and each ofthe first and the second dispensing orifices are separated by up to 2times the width of the respective dispensing orifice. The spacingbetween orifices is sufficient to maintain a distance between adjacentstrands as they exit the die. This spacing accommodates die swell at thedispensing tip. This spacing between orifices allows the strands afterextrusion at different speeds to repeatedly collide with each other toform the repeating bonds of the net. If the spacing between orifices istoo great the strands will not collide with each other and will not formthe net.

In general, it has been observed that the rate of strand bonding isproportional to the extrusion speed of the faster strand. Further, ithas been observed that this bonding rate can be increased, for example,by increasing the polymer flow rate for a given orifice size, or bydecreasing the orifice area for a given polymer flow rate. It has alsobeen observed that the distance between bonds is inversely proportionalto the rate of strand bonding, and proportional to the speed that thenet is drawn away from the die. Thus, it is believed that the distancebetween bonds and the net basis weight can be independently controlledby design of the orifice cross sectional area, the takeaway speed, andthe extrusion rate of the polymer. For example, relatively high basisweight nettings, with a relatively short bond pitch can be made byextruding at a relatively high polymer flow rate, with a relatively lownetting takeaway speed, using a die with a relatively small strandorifice area.

The size (same or different) of the strands can be adjusted, forexample, by the composition of the extruded polymers, velocity of theextruded strands, and/or the orifice design (e.g., cross sectional area(e.g., height and/or width of the orifices)). For example, a firstpolymer orifice that is 3 times greater in area than the second polymerorifice can generate a net with equal strand sizes while meeting thevelocity difference between adjacent strands.

Referring now to FIG. 7, a schematic perspective view of a portion ofextrusion die 22 is illustrated, supplied with polymeric material andforming a net. Polymer from first cavity 92 a emerges as first strands100 a from first dispensing orifices 96 a, and second strands 100 b areemerging from second dispensing orifices 96 b. Passageways 98 a (hiddenbehind the nearest shim in this view) and 98 b, and the pressures incavities 92 a and 92 b are typically selected so that the strand speedof first strands 100 a are between about 2 and 6 (in some embodiments, 2and 4) times greater than the strand speed of second strands 100 b.

Although in the embodiment shown in FIG. 7, the first and seconddispensing orifices are collinear, this is not a requirement. In someembodiments, the first dispensing orifices are collinear with eachother, and the second dispensing orifices are collinear with each other,but the first and second dispensing orifices are not collinear. When thefirst and second dispensing orifices are not collinear with each other,it may be desirable to extrude the strands horizontally.

Referring now to FIG. 7 a, a schematic perspective view of anotherexemplary apparatus 20 a with a different arrangement of extrusion die22 relative to the nip 40 is shown. In alternate apparatus 20 a,extrusion die 22 is positioned so that the polymeric netting 24 isdispensed onto forming roll 44 and carried on that roller into the nipbetween forming roll 44 and backup roller 42. By positioning extrusiondie 22 quite close to forming roll 44, there is little time for thestrands that make up polymeric netting 24 to sag and extend under theforce of gravity. An advantage provided by this positioning is thatopenings 56 a in polymer backing 50 a tend to be rounder. More in thisregard can be achieved by extruding not only very close to one of therolls forming nip 40, but also at an extrusion speed similar to thecircumferential speed of that roll. In FIG. 7 a, again for visualclarity, upstanding posts on the polymer backing 50 a are not shownalong with openings 56 a.

Referring now to FIG. 7 b, a schematic perspective view of anotherexemplary apparatus 20 b with an alternate forming roll 44 b is shown.The surface of alternate forming roll 44 b includes raised areas 44 b′with cavities 46 having the inverse shape of upstanding posts. Raisedareas 44 b′ apply more nipping force on polymeric netting 24 againstbackup roll 42 than the other areas of nip forming roll 44 b. In thedepicted embodiment, enough force has been applied by raised areas 44 b′that openings 56 in polymeric backing 50 b are separated by longitudinalbands 50 b′ of solid layer where the potential openings have beencrushed completely closed within nip 40 and where the forming roll 44 b′provides bands 50 b′ with upstanding posts 62. Further, the relativethickness of the extruded polymeric netting has been found to affect therange of hole sizes; with a relatively thick netting it is easier to nipthe melt to form longitudinal bands 50 b′ of solid film.

In the embodiments shown in FIGS. 1, 7 a, and 7 b and in some otherembodiments of the method disclosed herein in which net extrudate is fedonto a continuously moving forming surface with cavities having theinverse shape of the upstanding posts, pressure provided by the nipforces the resin into the cavities. In some embodiments, a vacuum can beused to evacuate the cavities for easier filling of the cavities. Theforming surface and cavities can optionally be air or water cooledbefore stripping the mechanical fastening net having upstanding postsfrom the forming surface such as by a stripper roll.

Suitable technologies for making cavities in a roll include employing aseries of plates defining a plurality of post-forming cavities about itsperiphery such as those described, for example, in U.S. Pat. No.4,775,310 (Fischer). Cavities may be formed in the plates by drilling orphotoresist technology, for example. Other suitable rolls with cavitiesmay include wire-wrapped rolls, which are disclosed along with theirmethod of manufacturing, for example, in U.S. Pat. No. 6,190,594 (Gormanet al.). Yet other suitable tool rolls are described in U.S. Pat. No.6,287,665 (Hammer), U.S. Pat. No. 7,198,743 (Tuma), and U.S. Pat. No.6,627,133 (Tuma). Another suitable forming surface includes using aflexible mold belt defining an array of upstanding post-shaped cavitiesas described in U.S. Pat. No. 7,214,334 (Jens et al.). Fornon-continuous processes, cavities can be drilled into plates (e.g.,laser-drilled into silicone plates) used in a film press, for example.

In some embodiments, it may be desirable to pattern the second majorsurface of the polymeric backing. This can be achieved, for example, bypatterning the surface of backup roller 42 shown in FIGS. 1, 7 a, and 7b. Cavities in the backup roller 42 can provide upstanding posts on boththe second major surface while the forming roll 44 or 44 b providesupstanding posts on the first major surface of the polymeric backing.However, in some embodiments, the upstanding posts are on only the firstmajor surface of the polymeric backing. This may be useful, for example,when joining the second major surface to a carrier as described infurther detail below. The use of a textured roller, for example, for thebackup roller 42, or providing nip roller 44 with additional surfacetexture, may be useful to preferentially move polymer in the crossdirection or downweb direction. This can be useful for shaping theopenings on one or both sides of the polymeric backing. Also, in someembodiments, it may be desired to quench one side of the film at afaster rate than the other, in order to affect the shape of theopening's cross-section.

While the embodiment of the method described above in connection withFIGS. 3 to 7 supply first and second strands of a polymer net fromseparate first and second cavities, other embodiments include providingan extrusion die comprising a plurality of shims positioned adjacent toone another, the shims together defining a cavity, the extrusion diehaving a plurality of first dispensing orifices in fluid communicationwith the cavity and a plurality of second dispensing orifices in fluidcommunication with the cavity, such that the first and second dispensingorifices are alternated. In these embodiments, first polymeric strandsare dispensed from the first dispensing orifices at a first strand speedwhile simultaneously second polymeric strands are dispensed from thesecond dispensing orifices at a second strand speed, wherein the firststrand speed is at least 2 times the second strand speed. In someembodiments, the cavity of the extrusion die is supplied with a firstpolymer at a first pressure so as to dispense a first strand at a firststrand speed through a first passageway, and to dispense a second strandat a second strand speed through a second passageway, wherein the firststrand speed is at least 2 (in some embodiments, 2 to 6, or even 2 to 4)times the second strand speed, such that a polymer net comprising firstand second polymeric strands is formed.

Referring now to FIG. 11, a plan view of shim 4440, useful in connectionwith a die for forming netting with first and second strands made fromthe same material and extruded from a single cavity, is illustrated.Shim 4440 has aperture 4460. When assembled with the shims of FIGS. 12and 13 in the way described below in FIGS. 14 and 15, aperture 4460 willdefine at least a portion of cavity 4462. In use, passageway 4468conducts polymer from cavity 4462 to first dispensing orifice 4466 ondispensing surface 4467. Importantly, there is restriction 4470 adjacentto first dispensing orifice 4466. Restriction 4470 increases the firststrand speed of the first strand emerging from first dispensing orifice4466 during use.

Referring now to FIG. 12, a plan view of shim 4540 is illustrated. Shim4540 has an aperture 4560. When assembled with the shims of FIGS. 11 and13 in the way described below in FIGS. 14 and 15, aperture 4560 willdefine at least a portion of cavity 4462. In use, passageway 4568conducts polymer from cavity 4462 to second dispensing orifice 4566 ondispensing surface 4567. There is restriction 4570 set back from seconddispensing orifice 4566. The wide orifice 4566 decreases the speed ofthe second strand emerging from second dispensing orifice 4566 duringuse.

Referring now to FIG. 13, a plan view of spacer shim 4640 useful informing netting in conjunction with the shims 4440 and 4540 of FIGS. 11and 12, is illustrated Shim 4640 has cut-out 4660. When assembled withthe shims of FIGS. 11 and 12 in the way described below in FIGS. 14 and15, cut-out 4660 will define at least a portion of cavity 4462. Cut-out4660 has open end 4661 on the end opposite dispensing surface 4667. Openend 4661 allows the inflow of polymer into cavity 4462 when assembledwith the other shims and mounted in a die mount analogous to that shownabove in FIG. 3.

Referring now to FIG. 14, a detail perspective view of plurality ofshims 4741 formed, from left to right, one spacer shim 4640, one shim4540, one spacer shim 4640, and one shim 4440, is illustrated. In thisview it can be appreciated how apertures 4460 and 4560, and cut-out 4660(not labeled) together define a portion of cavity 4462. It will beapparent to the skilled artisan that for any particular extrusionpressure applied to cavity 4462 during extrusion, the mass flow of thefirst strand emerging from first dispensing orifice 4466 will beapproximately equal to the mass flow of the second strand emerging fromsecond dispensing orifice 4566. However, the first strand speed of thefirst strand will be significantly faster than the second strand speedof the second strand.

Referring now to FIG. 15, a detail perspective view of the plurality ofshims of FIG. 14, seen from the reverse angle, with the nearest instanceof shim 4640 removed for visual clarity, is illustrated. In this view ofthe reduced plurality of shims 4741′, restriction 4570 can be betterappreciated.

Further details about the formation of nets from extrusion dies havingone or more cavities can be found in co-pending application having U.S.Ser. No. 61/526,001, filed Aug. 22, 2011, the disclosure of which isincorporated herein by reference.

Examples of polymeric materials from which the mechanical fastening netcan be made include thermoplastic polymers. Suitable thermoplasticpolymers for mechanical fasteners include polyolefin homopolymers suchas polyethylene and polypropylene, copolymers of ethylene, propyleneand/or butylene; copolymers containing ethylene such as ethylene vinylacetate and ethylene acrylic acid; polyesters such as poly(ethyleneterephthalate), polyethylene butyrate and polyethylene napthalate;polyamides such as poly(hexamethylene adipamide); polyurethanes;polycarbonates; poly(vinyl alcohol); ketones such aspolyetheretherketone; polyphenylene sulfide; and mixtures thereof.Typically, the thermoplastic is a polyolefin (e.g., polyethylene,polypropylene, polybutylene, ethylene copolymers, propylene copolymers,butylene copolymers, and copolymers and blends of these materials).

In some embodiments, polymeric materials from which the mechanicalfastening net can be made comprise a colorant (e.g., pigment and/or dye)for functional (e.g., optical effects) and/or aesthetic purposes (e.g.,each has different color/shade). Suitable colorants are those known inthe art for use in various polymeric materials. Exemplary colorsimparted by the colorant include white, black, red, pink, orange,yellow, green, aqua, purple, and blue. In some embodiments, it isdesirable level to have a certain degree of opacity for one or more ofthe polymeric materials. The amount of colorant(s) to be used inspecific embodiments can be readily determined by those skilled in the(e.g., to achieve desired color, tone, opacity, transmissivity, etc.).

In some embodiments, nets comprising strands of polymer useful for themethod described herein include alternating first and second polymericstrands, wherein the first and second polymeric strands comprisedifferent polymeric compositions. These nets can be prepared, forexample, by extrusion using any embodiments of the method describedabove in which the extrusion die includes first and second cavities. Thedifferent polymeric compositions in the first and second strands may beselected for their surface properties or their bulk properties (e.g.,tensile strength, elasticity, color, etc). Furthermore, polymericcompositions can be selected to provide specific functional or aestheticproperties in the mechanical fastening net such as elasticity, softness,hardness, stiffness, bendability, or colors. The first and secondpolymer strands may have the same or different colors.

In some embodiments, a single strand of the strands of polymer in thenet may include different polymeric compositions. For example, one ormore of the strands in the net may have a core made of one polymericcomposition and a sheath of a different polymeric composition. Such netscan be extruded as described in co-pending application having U.S. Ser.No. 61/530,521, filed Sep. 2, 2011, the disclosure of which isincorporated herein by reference. A portion of the polymer in these netscan be molded into upstanding posts immediately after extrusion whilestill molten as described above but this is not a requirement.

In embodiments in which the strands of polymer in the net useful formaking a mechanical fastening net described herein include two differentpolymeric compositions, the first polymeric composition may be athermoplastic polymer as described above, and the second polymericcomposition may be a more elastic composition. For example, the secondpolymeric composition may include thermoplastic elastomers such as ABAblock copolymers, polyurethane elastomers, polyolefin elastomers (e.g.,metallocene polyolefin elastomers), polyamide elastomers, ethylene vinylacetate elastomers, and polyester elastomers. An ABA block copolymerelastomer generally is one where the A blocks are polystyrenic, and theB blocks are conjugated dienes (e.g., lower alkylene dienes). Inembodiments described above in which at least some of the polymerstrands in the net are core/sheath strands, it may useful for the coreto comprise a relative more elastic composition.

In any embodiments of the method described above in which a net isextruded, polymers used to make the polymeric strands are selected to becompatible with each other such that the first and second strands bondtogether as the bond regions. Bonding generally refers to melt-bonding,and the bonds between polymer strands can be considered to bemelt-bonded. The bonding occurs in a relatively short period of time(typically less than 1 second). The bond regions, as well as thestrands, typically cool through air and natural convection and/orradiation. In selecting polymers for the strands, in some embodiments,it may be desirable to select polymers of bonding strands that havedipole interactions (or H-bonds) or covalent bonds. Bonding betweenstrands has been observed to be improved by increasing the time that thestrands are molten to enable more interaction between polymers. Bondingof polymers has generally been observed to be improved by reducing themolecular weight of at least one polymer and or introducing anadditional co-monomer to improve polymer interaction and/or reduce therate or amount of crystallization. In some embodiments, the distancebetween bonds is in a range from 0.5 mm to 20 mm (in some embodiments,in a range from 0.5 mm to 10 mm).

In any embodiments of the method described above in which a net isextruded, the strands of polymer typically do not substantially crossover each other (i.e., at least 50 (at least 55, 60, 65, 70, 75, 80, 85,90, 95, 99, or even 100) percent by number do not cross over eachother).

According to some embodiments of the method disclosed herein, mechanicalfastening nets can be made by at least one of passing through a nip orcalendering any net comprising strands of polymer and open areas betweenthe strands of polymer, whether made by the above-described extrusionmethods or not. Such nets can be made from any of the polymers describedabove in connection with extrusion methods for making a net.

When the polymeric strands of the net, including any net whetherprepared according to the extrusion methods described above or not, aresolid instead of molten, molding the upstanding posts can includepressing the net onto a heated mold surface with cavities having theinverse shape of the upstanding posts. This mold surface may be movingas described above or stationary. In these embodiments, the polymericbacking in the resulting mechanical fastening net tends to have a rangeof thicknesses, and the polymer backing tends to be thinnest where itabuts an opening. Also, in many of these embodiments, the openings haveirregularly formed perimeters. This can mean that the openings haveirregular shapes (that is, no lines of symmetry). They may have edgesthat are not smooth (e.g., jagged or feathery edges). Irregularly formedopenings can also have a variety of thicknesses of the backingsurrounding the openings. These features can depend, for example, on thetemperature and length of time used during the molding as well as on theselection polymeric material in the net.

In some embodiments, the strands of polymer in the net useful for themethod of making the mechanical fastening net disclosed herein have anaverage width in a range from 10 micrometers to 500 micrometers (in arange from 10 micrometers to 400 micrometers, or even 10 micrometers to250 micrometers).

In some embodiments, the net comprising strands of polymer useful forthe method of making the mechanical fastening net disclosed herein havea basis weight in a range from 5 g/m² to 400 g/m² (in some embodiments,10 g/m² to 200 g/m²).

In some embodiments, the net comprising strands of polymer useful in themethod of making the mechanical fastening net disclosed herein has athickness up to 2 mm (in some embodiments, up to 1 mm, 500 micrometers,250 micrometers, 100 micrometers, 75 micrometers, 50 micrometers, oreven up to 25 micrometers; in a range from 10 micrometers to 750micrometers, 10 micrometers to 750 micrometers, 10 micrometers to 500micrometers, 10 micrometers to 250 micrometers, 10 micrometers to 100micrometers, 10 micrometers to 75 micrometers, 10 micrometers to 50micrometers, or even 10 micrometers to 25 micrometers. In someembodiments, the net comprising strands of polymer has an averagethickness in a range from 250 micrometers to 5 mm. In some embodiments,the net comprising strands of polymer has an average thickness notgreater than 5 mm.

The upstanding posts molded in the strands of the net in any of themethods and mechanical fastening nets described herein may haveloop-engaging heads that have an overhang or may be upstanding postshaving distal tips that can be formed into loop-engaging heads, ifdesired. The term “loop-engaging” as used herein relates to the abilityof a male fastening element to be mechanically attached to a loopmaterial. Generally, male fastening elements with loop-engaging headshave a head shape that is different from the shape of the post. Forexample, the male fastening element with a loop-engaging head may be inthe shape of a mushroom (e.g., with a circular or oval head enlargedwith respect to the stem), a hook, a palm-tree, a nail, a T, or a J. Theloop-engageability of male fastening elements may be determined anddefined by using standard woven, nonwoven, or knit materials. A regionof male fastening elements with loop-engaging heads generally willprovide, in combination with a loop material, at least one of a higherpeel strength, higher dynamic shear strength, or higher dynamic frictionthan a region of posts without loop-engaging heads. Typically, malefastening elements that have loop-engaging heads have a maximumthickness dimension (in either dimension normal to the height) of up toabout 1 (in some embodiments, 0.9, 0.8, 0.7, 0.6, 0.5, or 0.45)millimeter. In some embodiments, the male fastening elements have amaximum height (above the backing) of up to 3 mm, 1.5 mm, 1 mm, or 0.5mm and, in some embodiments a minimum height of at least 0.05 mm, 0.1mm, or 0.2 mm. In some embodiments, the upstanding posts have aspectratio (that is, a ratio of height to width at the widest point) of atleast about 2:1, 3:1, or 4:1.

Male fastening elements that have “loop-engaging overhangs” or“loop-engaging heads” do not include ribs that are precursors tofastening elements (e.g., elongate ribs that are profile extruded andsubsequently cut to form male fastening elements upon stretching in thedirection of the ribs). Such ribs would not be able to engage loopsbefore they are cut and stretched. Such ribs would also not beconsidered upstanding posts. Furthermore, portions cut from such ribsare noticeable different from the molded posts described herein as wouldbe seen by a person having ordinary skill in the art. For example,molded posts do not typically have flat sides such as those that areformed by cutting.

If the posts formed upon exiting the cavities do not have loop-engagingheads, loop-engaging heads could be subsequently formed by a cappingmethod as described in U.S. Pat. No. 5,077,870 (Melbye et al.).Typically, the capping method includes deforming the tip portions of theupstanding posts using heat and/or pressure. The heat and pressure, ifboth are used, could be applied sequentially or simultaneously. Themethod of making a mechanical fastening net disclosed herein can alsoinclude a step in which the shape of the cap is changed, for example, asdescribed in U.S. Pat. No. 6,132,660 (Kampfer).

In some embodiments of the mechanical fastening net or the method ofmaking a mechanical fastening net disclosed herein, each upstanding posthas a cap with loop engaging overhangs extending in multiple (i.e., atleast two) directions. For example, the upstanding post may be in theshape of a mushroom, a nail, a palm tree, or a T. In some embodiments,the upstanding posts are provided with a mushroom head (e.g., with anoval or round cap distal from the polymer backing). In otherembodiments, the upstanding posts may have the shape of a J (e.g., asshown in U.S. Pat. No. 5,953,797 (Provost et al.).

In some embodiments of the mechanical fastening net according to and/ormade according to the present disclosure, the upstanding posts have amaximum height (above the backing) of up to 3 mm, 1.5 mm, 1 mm, or 0.5mm and, in some embodiments a minimum height of at least 0.05 mm, 0.1mm, or 0.2 mm. In some embodiments, the upstanding posts have aspectratio (that is, a ratio of height to width at the widest point) of atleast about 2:1, 3:1, or 4:1.

In some embodiments of the mechanical fastening net according to and/ormade according to the present disclosure, in at least some locations ofthe polymeric backing between the openings, there is a plurality of theupstanding posts. In some of these embodiments, the plurality of theupstanding posts is provided in multiple rows of upstanding posts, eachrow having at least two upstanding posts. This can be seen, for example,in many locations in the mechanical fastening nets shown in FIGS. 9 and17. While FIGS. 9 and 17 illustrate the upstanding posts are formed inrows, in other embodiments, the upstanding posts may be formed in arandom pattern.

In some embodiments of the mechanical fastening net according to and/ormade according to the present disclosure, in at least some locations ofthe polymeric backing between the openings, the locations are larger ineach dimension than at least the bases of the upstanding posts. This canalso be seen, for example, in many locations in the mechanical fasteningnets shown in FIGS. 9 and 17.

In some embodiments of the mechanical fastening net according to and/ormade according to the present disclosure, the strands from the net arestill visible after a portion of the strands are molded into upstandingposts. This can be seen, for example, in FIG. 9. In other embodiments,the strands from the net are no longer visible after a portion of thestrands are molded into upstanding posts. This can be seen, for example,in FIG. 17.

In some embodiments, mechanical fastening nets according to and/or madeaccording to the present disclosure have a backing thickness (notincluding the upstanding posts) up to 200 micrometers (in someembodiments, up to 150 micrometers, 100 micrometers, 75 micrometers, or50 micrometers; in a range from 10 micrometers to 200 micrometers, 10micrometers to 150 micrometers, 10 micrometers to 100 micrometers, 30micrometers to 200 micrometers, 30 micrometers to 150 micrometers, 30micrometers to 100 micrometers, or 30 micrometers to 75 micrometers.

In some embodiments, mechanical fastening nets described herein have atotal open area for each of the first and second, generally opposedmajor surfaces of not greater than 50 (in some embodiments, not greaterthan 45, 40, 35, 30, 25, 20. 15, 10, 5, 4 3, 2, 1, 0.75, 0.5, 0.25, oreven not greater than 0.1) percent of the total area of the respectivemajor surface.

In some embodiments, for at least a majority of the openings of themechanical fastening nets described herein, the maximum area of eachopening is not greater than is 5 (in some embodiments, not greater than2.5, 2, 1, 0.5, 0.1, 0.05, 0.01, 0.075, or even not greater than0.005)mm². Individual openings range from 0.005 mm² to 5 mm² In someembodiments, the openings have widths in a range from 5 micrometers to 1mm (in some embodiments, 10 micrometers to 0.5 mm) In some embodiments,the openings have lengths in a range from 100 micrometers to 10 mm (insome embodiments, 100 micrometers to 1 mm) In some embodiments, formechanical fastening nets described herein the openings have a length towidth ratio in a range from 1:1 to 100:1, (in some embodiments, 1:1 to1.9:1, 2:1 to 100:1 2:1 to 75:1, 2:1 to 50:1, 2:1 to 25:1, or even, 2:1to 10:1).

In some embodiments, mechanical fastening nets according to the presentdisclosure have in a range from 50,000 to 6,000,000 (in someembodiments, 100,000 to 6,000,000, 500,000 to, 6,000,000, or even1,000,000 to 6,000,000) openings/m².

In some embodiments, the openings of the mechanical fastening netsdescribed herein have at least two pointed ends. In some embodiments, atleast some of the openings are elongated with two pointed ends. In someembodiments, at least some of the openings are elongated with twoopposed pointed ends. In some embodiments, at least some of the openingsare ovals.

In some embodiments of the mechanical fastening net or the method ofmaking the mechanical fastening net according to the present disclosure,the mechanical fastening net may be stretched in at least one direction.In a continuous process (e.g., after the mechanical fastening net exitsfrom the nip) monoaxial stretching in the machine direction can beperformed by propelling the web over rolls of increasing speed. Meanssuch as diverging rails and diverging disks are useful forcross-direction stretching. A versatile stretching method that allowsfor monoaxial, sequential biaxial, or simultaneous biaxial stretching ofa thermoplastic web employs a flat film tenter apparatus. Such anapparatus grasps the thermoplastic web using a plurality of clips,grippers, or other film edge-grasping means along opposing edges of thethermoplastic web in such a way that monoaxial, sequential biaxial, orsimultaneous biaxial stretching in the desired direction is obtained bypropelling the grasping means at varying speeds along divergent rails.Increasing clip speed in the machine direction generally results inmachine-direction stretching. Monoaxial and biaxial stretching can beaccomplished, for example, by the methods and apparatus disclosed inU.S. Pat. No. 7,897,078 (Petersen et al.) and the references citedtherein. Flat film tenter stretching apparatuses are commerciallyavailable, for example, from Brückner Maschinenbau GmbH, Siegsdorf,Germany. The term “machine direction” (MD) as used above and belowdenotes the direction of a running, continuous web of the net during themanufacturing of the mechanical fastening net. The term“cross-direction” (CD) as used above and below denotes the directionwhich is essentially perpendicular to the machine direction.

In some embodiments, the mechanical fastening net according to and/ormade according to the present disclosure is joined to a carrier (e.g.,even a sacrificial carrier) for ease of handling or for making afastening laminate for a selected application. The mechanical fasteningnet may be joined to a carrier, for example, by lamination (e.g.,extrusion lamination), adhesives (e.g., pressure sensitive adhesives),or other bonding methods (e.g., ultrasonic bonding, compression bonding,or surface bonding).

The carrier may be continuous (i.e., without any through-penetratingholes) or discontinuous (e.g. comprising through-penetratingperforations or pores). The carrier may comprise a variety of suitablematerials including woven webs, non-woven webs (e.g., spunbond webs,spunlaced webs, airlaid webs, meltblown web, and bonded carded webs),textiles, plastic films (e.g., single- or multilayered films, coextrudedfilms, laterally laminated films, or films comprising foam layers), andcombinations thereof In some embodiments, the carrier is a fibrousmaterial (e.g., a woven, nonwoven, or knit material). Examples ofmaterials for forming thermoplastic fibers include polyolefins (e.g.,polyethylene, polypropylene, polybutylene, ethylene copolymers,propylene copolymers, butylene copolymers, and copolymers and blends ofthese polymers), polyesters, and polyamides. The fibers may also bemulti-component fibers, for example, having a core of one thermoplasticmaterial and a sheath of another thermoplastic material. In someembodiments, the carrier comprises multiple layers of nonwoven materialswith, for example, at least one layer of a meltblown nonwoven and atleast one layer of a spunbonded nonwoven, or any other suitablecombination of nonwoven materials. For example, the carrier may be aspunbond-meltbond-spunbond, spunbond-spunbond, orspunbond-spunbond-spunbond multilayer material. Or, the carrier may be acomposite web comprising a nonwoven layer and a dense film layer. Usefulcarriers may have any suitable basis weight or thickness that is desiredfor a particular application. For a fibrous carrier, the basis weightmay range, e.g., from at least about 5, 8, 10, 20, 30, or 40 grams persquare meter, up to about 400, 200, or 100 grams per square meter. Thecarrier may be up to about 5 mm, about 2 mm, or about 1 mm in thicknessand/or at least about 0.1, about 0.2, or about 0.5 mm in thickness.

In some embodiments where the mechanical fastening net includes athermoplastic backing, the thermoplastic backing can be joined to afibrous web carrier using surface bonding or loft-retaining bondingtechniques. The term “surface-bonded” when referring to the bonding offibrous materials means that parts of fiber surfaces of at leastportions of fibers are melt-bonded to the second surface of the backing,in such a manner as to substantially preserve the original (pre-bonded)shape of the second surface of the backing, and to substantiallypreserve at least some portions of the second surface of the backing inan exposed condition, in the surface-bonded area. Quantitatively,surface-bonded fibers may be distinguished from embedded fibers in thatat least about 65% of the surface area of the surface-bonded fiber isvisible above the second surface of the backing in the bonded portion ofthe fiber. Inspection from more than one angle may be necessary tovisualize the entirety of the surface area of the fiber. The term“loft-retaining bond” when referring to the bonding of fibrous materialsmeans a bonded fibrous material comprises a loft that is at least 80% ofthe loft exhibited by the material prior to, or in the absence of, thebonding process. The loft of a fibrous material as used herein is theratio of the total volume occupied by the web (including fibers as wellas interstitial spaces of the material that are not occupied by fibers)to the volume occupied by the material of the fibers alone. If only aportion of a fibrous web has the second surface of the backing bondedthereto, the retained loft can be easily ascertained by comparing theloft of the fibrous web in the bonded area to that of the web in anunbonded area. It may be convenient in some circumstances to compare theloft of the bonded web to that of a sample of the same web before beingbonded, for example, if the entirety of fibrous web has the secondsurface of the backing bonded thereto. In some of these embodiments, thejoining comprises impinging heated gaseous fluid (e.g., ambient air,dehumidified air, nitrogen, an inert gas, or other gas mixture) onto afirst surface of the fibrous web carrier while it is moving; impingingheated fluid onto the second surface of the backing while the continuousweb is moving, wherein the second surface is opposite the fibrous layer,loop, or upstanding posts the backing; and contacting the first surfaceof the fibrous web with the second surface of the backing so that thefirst surface of the fibrous web is melt-bonded (e.g., surface-bonded orbonded with a loft-retaining bond) to the second surface of the backing.Impinging heated gaseous fluid onto the first surface of the fibrous weband impinging heated gaseous fluid on the second surface of the backingmay be carried out sequentially or simultaneously. Further methods andapparatus for joining a continuous web to a fibrous carrier web usingheated gaseous fluid may be found in U.S. Pat. Appl. Pub. Nos.2011/0151171 (Biegler et al.) and 2011/0147475 (Biegler et al.).

In some embodiments wherein the mechanical fastening net is joined to acarrier, one or more zones of the carrier may comprise one or moreelastically extensible materials extending in at least one directionwhen a force is applied and returning to approximately their originaldimension after the force is removed. However, in some embodiments, atleast the portion of the carrier joined to the multiple strands of thebacking or loop material is not stretchable. In some embodiments, theportion of carrier joined to the multiple strands will have up to a 10(in some embodiments, up to 9, 8, 7, 6, or 5) percent elongation in theCD. In some embodiments, the carrier may be extensible but nonelastic.In other words, the carrier may have an elongation of at least 5, 10,15, 20, 25, 30, 40, or 50 percent but substantially no recovery from theelongation (e.g., up to 10 or 5 percent recovery). Suitable extensiblecarriers may include nonwovens (e.g., spunbond, spunbond meltblownspunbond, or carded nonwovens). In some embodiments, the nonwoven may bea high elongation carded nonwoven (e.g., HEC). In some embodiments, thecarrier is not pleated. The term “elastic” refers to any material thatexhibits recovery from stretching or deformation. “Elongation” in termsof percent refers to {(the extended length−the initial length)/theinitial length} multiplied by 100.

In some embodiments wherein the mechanical fastening net is joined to acarrier, the carrier is provided with a layer of adhesive. In some ofthese embodiments, the mechanical fastening net is bonded to the carrierwith the adhesive to form a laminate, and the adhesive is exposed atleast some of the openings.

In some embodiments, the method according to the present disclosureincludes cutting a running length of the mechanical fastening net in theCD to provide a mechanical fastening patch. Such cutting can be carriedout, for example, after the mechanical fastening net is laminated to acarrier, and the patch can be considered a fastening laminate.

The fastening laminates made by the methods disclosed herein are useful,for example, in absorbent articles. Absorbent articles may have at leasta front waist region, a rear waist region, and a longitudinal centerline bisecting the front waist region and the rear waist region, whereinat least one of the front waist region or the rear waist regioncomprises the fastening laminate disclosed herein. The fasteninglaminate may be in the form of a fastening tab or landing zone that isbonded to at least one of the front waist region or the rear waistregion. A fastening tab may extend outwardly from at least one of theleft longitudinal edge or the right longitudinal edge of the absorbentarticle. In other embodiments, the fastening laminate may be an integralear portion of the absorbent article. The carrier at the user's end of afastening tab may exceed the extension of the spread mechanicalfastening patch thereby providing a fingerlift. When the spreadmechanical fastening patch is used in a fastening tab, exposed adhesivethat may be present in some embodiments in at least some of the openingsof the mechanical fastening patch may be useful for “anti-flagging” orfor maintaining the disposable absorbent article in a rolled up stateafter use. Also when the mechanical fastening patch is used as afastening tab, exposed adhesive that may be present in some embodimentsbetween the multiple strands of the spread mechanical fastening patchmay be useful to provide a combination of mechanical and adhesivefastening. The fastening laminate made by the methods disclosed hereinmay also be useful, for example, for disposable articles such assanitary napkins.

The mechanical fasteners and laminates made according to the presentdisclosure may also be useful in many other fastening applications, forexample, assembly of automotive parts or any other application in whichreleasable attachment may be desirable.

Some Embodiments of the Disclosure

In a first embodiment, the present disclosure provides a method ofmaking a mechanical fastening net, the method comprising:

providing a net comprising strands of polymer and open areas between thestrands of polymer; and

molding a portion of the polymer in the strands of the net intoupstanding posts to form the mechanical fastening net.

In a second embodiment, the present disclosure provides the method ofthe first embodiment, wherein the strands are periodically bondedtogether at bond regions throughout the net.

In a third embodiment, the present disclosure provides the method of thefirst or second embodiment, wherein the strands do not cross each other.

In a fourth embodiment, the present disclosure provides the method ofany one of the first to third embodiments, wherein the strands ofpolymer are solid.

In a fifth embodiment, the present disclosure provides the method of thefourth embodiment, wherein molding comprises pressing the net onto aheated mold surface with cavities having the inverse shape of theupstanding posts.

In a sixth embodiment, the present disclosure provides the method of thefourth or fifth embodiment, wherein the mechanical fastening netcomprises a polymeric backing comprising first and second majorsurfaces, a plurality of openings in the polymeric backing extendingbetween the first and second major surfaces, and upstanding posts on atleast one of the first or second major surface of the polymeric backing,wherein between the openings, the polymeric backing has a range ofthicknesses ranging from minimum to maximum thickness, wherein for atleast a portion of the polymeric backing, the minimum thickness of thepolymeric backing is where it abuts one of the openings.

In a seventh embodiment, the present disclosure provides the method ofthe sixth embodiment, wherein the openings have irregularly formedperimeters.

In an eighth embodiment, the present disclosure provides the method ofany one of the first to third embodiments, wherein the strands ofpolymer are molten.

In a ninth embodiment, the present disclosure provides the method of theeighth embodiment, wherein providing the net comprises extruding thenet.

In a tenth embodiment, the present disclosure provides the method of theninth embodiment, wherein extruding the net comprises:

providing an extrusion die comprising a plurality of shims positionedadjacent to one another, the shims together defining a cavity, theextrusion die having a plurality of first dispensing orifices in fluidcommunication with the cavity and a plurality of second dispensingorifices in fluid communication with the cavity, such that the first andsecond dispensing orifices are alternated; and

dispensing first polymeric strands from the first dispensing orifices ata first strand speed while simultaneously dispensing second polymericstrands from the second dispensing orifices at a second strand speed,wherein the first strand speed is at least 2 times the second strandspeed to provide the net.

In an eleventh embodiment, the present disclosure provides the method ofthe ninth embodiment, wherein extruding the net comprises:

providing an extrusion die comprising a plurality of shims positionedadjacent to one another, the shims together defining a first cavity anda second cavity, the extrusion die having a plurality of firstdispensing orifices in fluid communication with the first cavity andhaving a plurality of second dispensing orifices connected to the secondcavity, such that the first and second dispensing orifices arealternated; and

dispensing first polymeric strands from the first dispensing orifices ata first strand speed while simultaneously dispensing second polymericstrands from the second dispensing orifices at a second strand speed,wherein the first strand speed is at least 2 times the second strandspeed to provide the net.

In a twelfth embodiment, the present disclosure provides the method ofany one of the eighth to eleventh embodiments, wherein molding a portionof the polymer in the strands of the net into upstanding postscomprises:

providing a net extrudate upon extruding the net; and

feeding the net extrudate onto a continuously moving forming surfacewith cavities having the inverse shape of the upstanding posts.

In a thirteenth embodiment, the present disclosure provides the methodof the twelfth embodiment, wherein the continuously moving formingsurface is a first roll that forms a nip with a second roll.

In a fourteenth embodiment, the present disclosure provides the methodof any one of the eighth to thirteenth embodiments, wherein themechanical fastening net comprises a polymeric backing comprising firstand second major surfaces, a plurality of openings in the polymericbacking extending between the first and second major surfaces, andupstanding posts on at least one of the first or second major surface ofthe polymeric backing, wherein between the openings, the polymericbacking has a range of thicknesses ranging from minimum to maximumthickness, wherein for at least a portion of the polymeric backing, theminimum thickness of the polymeric backing is where it abuts one of theopenings.

In a fifteenth embodiment, the present disclosure provides the method ofany one of the eighth to thirteenth embodiments, wherein the mechanicalfastening net comprises a polymeric backing comprising first and secondmajor surfaces, a plurality of openings in the polymeric backingextending between the first and second major surfaces, and upstandingposts on at least one of the first or second major surface of thepolymeric backing, wherein the openings each have a series of areasthrough the openings from the first to second major surfaces rangingfrom minimum to maximum areas, and wherein for at least a portion of theopenings, the minimum area is not at either the first or second majorsurface.

In a sixteenth embodiment, the present disclosure provides the method ofany one of the first to fifteenth embodiments, further comprisingdeforming at least some of the upstanding posts at their distal ends toform loop-engaging overhangs.

In a seventeenth embodiment, the present disclosure provides amechanical fastening net comprising a polymeric backing comprising firstand second major surfaces, a plurality of openings in the polymericbacking extending between the first and second major surfaces, andupstanding posts on at least one of the first or second major surface ofthe polymeric backing, wherein between the openings, the polymericbacking has a range of thicknesses ranging from minimum to maximumthickness, wherein for at least a portion of the polymeric backing, theminimum thickness of the polymeric backing is where it abuts one of theopenings.

In an eighteenth embodiment, the present disclosure provides themechanical fastening net of the seventeenth embodiment, wherein theopenings each have a series of areas through the openings from the firstto second major surfaces ranging from minimum to maximum areas, andwherein for at least a portion of the openings, the minimum area is notat either the first or second major surface.

In a nineteenth embodiment, the present disclosure provides themechanical fastening net of the seventeenth embodiment, the openingshave irregularly formed perimeters.

In a twentieth embodiment, the present disclosure provides a mechanicalfastening net comprising a polymeric backing comprising first and secondmajor surfaces, a plurality of openings in the polymeric backingextending between the first and second major surfaces, and upstandingposts on at least one of the first or second major surface of thepolymeric backing, wherein the openings each have a series of areasthrough the openings from the first to second major surfaces rangingfrom minimum to maximum areas, and wherein for at least a portion of theopenings, the minimum area is not at either the first or second majorsurface.

In a twenty-first embodiment, the present disclosure provides themechanical fastening net of any one of the seventeenth to twentiethembodiments, wherein the upstanding posts are on only the first majorsurface of the polymeric backing.

In a twenty-second embodiment, the present disclosure provides themechanical fastening net of any one of the seventeenth to twenty-firstembodiments, wherein in at least some locations of the polymeric backingbetween the openings, there is a plurality of the upstanding posts.

In a twenty-third embodiment, the present disclosure provides themechanical fastening net of any one of the seventeenth to twenty-secondembodiments, wherein the plurality of the upstanding posts is providedin multiple rows of upstanding posts, each row having at least twoupstanding posts.

In a twenty-fourth embodiment, the present disclosure provides themechanical fastening net of any one of the seventeenth to twenty-thirdembodiments, wherein for at least some locations of the polymericbacking between the openings, the locations have a length and a widthperpendicular to the thickness of the net, and wherein the length andwidth are both larger than at least the bases of the upstanding posts.

In a twenty-fifth embodiment, the present disclosure provides themechanical fastening net of any one of the seventeenth to twenty-fourthembodiments, wherein there is a total area and a total open area foreach of the first and second major surfaces, and wherein the total openarea for each of the first and second major surfaces is not greater than50 percent of the total area of the respective major surface.

In a twenty-sixth embodiment, the present disclosure provides themechanical fastening net of any one of the seventeenth to twenty-fifthembodiments, having a thickness of up to 200 micrometers.

In a twenty-seventh embodiment, the present disclosure provides alaminate comprising the mechanical fastening net of any one of theseventeenth to twenty-sixth embodiments joined to a carrier.

In a twenty-eighth embodiment, the present disclosure provides thelaminate of the twenty-seventh embodiment, wherein the mechanicalfastening net is joined to the carrier with adhesive.

In a twenty-ninth embodiment, the present disclosure provides thelaminate of the twenty-eighth embodiment, wherein the adhesive isexposed in at least some of the openings.

In a thirtieth embodiment, the present disclosure provides the method ofany one of the first to sixth embodiments, wherein the strands ofpolymer are not all the same color.

Advantages and embodiments of this invention are further illustrated bythe following examples, but the particular materials and amounts thereofrecited in these examples, as well as other conditions and details,should not be construed to unduly limit this invention. All parts andpercentages are by weight unless otherwise indicated.

EXAMPLES Example 1

A co-extrusion die as generally depicted in FIG. 3, and assembled with a10 shim repeating pattern of extrusion orifices as generally illustratedin FIG. 7, was prepared. The thickness of the shims in the repeatsequence was 4 mils (102 mm) for shims 70 with connection to the firstcavity, the second cavity, and for the spacers which had no connectionto either cavity (70 a, 70 b and 70 c, respectively). The shims wereformed from stainless steel, with perforations cut by a wire electrondischarge machining. The height of first and second extrusion orifices96 a and 96 b was cut to 30 mils (0.762 mm). The extrusion orifices werealigned in a collinear, alternating arrangement, and resultingdispensing surface 97 was as shown generally in FIG. 8. Two spacer shimsfollowed by two shims with connection to the first cavity, followed bytwo spacer shims, followed by 4 shims with connection to the secondcavity comprises the shim stack sequence. The total width of the shimsetup was 15 cm. The orifice width for first extrusion orifices 96 aleading to the first cavity was 0.204 mm, and the orifice width forsecond extrusion orifices 96 b leading to the second cavity was 0.408mm. The land spacing between the first and second orifices was 0.204 mm.

The inlet fittings on the two end blocks were each connected to aconventional single-screw extruder. The extruder feeding the firstcavity was loaded with thirty-five melt flow index polypropylenecopolymer pellets (obtained under the trade designation “C700-35N” fromDow Chemical Company, Midland, Mich.). The extruder feeding the secondcavity was also loaded with thirty-five melt flow index polypropylenecopolymer pellets (“C700-35N”) and a 2% loading of blue pigmentmasterbatch.

The net was extruded vertically into an extrusion quench takeaway nip.The quench nip had a metal surface provided with 1600 cavities persquare inch and was set to a temperature of 150° C. The nip pressure wassufficient to fill the cavities to a height of 0.350 mm. Polymers wereextruded from the two cavities at appropriate flow rates to make a net,and the quench take away speed was 13.0 meters per minute. A schematicof the process is shown in FIG. 1.

Using an optical microscope, the backing thickness and upstanding postheight of the mechanical fastening net were measured. The backingthickness ranged from 0.060 mm to 0.070 mm, and the height of the postswas 0.0350 mm. The general shape of the openings was vesica piscis.

An optical digital photo at 10× of the mechanical fastening net is shownin FIG. 9. An optical digital photo taken from the side at 150× is shownin FIG. 10. It can be seen in the side view that the backing thicknessis at a minimum where it abuts an opening. It can also been seen in theside view that minimum area of the openings are in the interior of thebacking and not at either the first or second major surface.

The upstanding posts could be capped using a variety of capping methods.

Example 2

Polypropylene netting (style NFNC 605-002) was obtained from Conwed,(Minneapolis, Minn.). A photo of the polypropylene netting is shown inFIG. 16. A film press obtained from (Wabash MPI, Wabash, Ind.), was usedto form upstanding posts in the polypropylene netting. The platens ofthe film press were preheated to 350° F. (177° C.). A sandwich was thenmade by assembling a smooth steel plate approximately 0.125 inch (3.2mm) thick, a 20-mil (0.51-mm) thick silicone plate with laser-drilledholes to produce posts, the polypropylene netting, 1 sheet of 4 mil (0.1mm) polyethylene terephthalate (PET) film, and a second smooth steelplate approximately 0.125 inch (3.2 mm) thick. The holes had diametersof a nominal 325 micrometers. The sandwich was placed between theplatens at low pressure to warm up the sandwich plates. Then the 6-inch(15 cm) by 6-inch (15 cm) sample was pressed at approximately 10 tons(the pressure was 3.8 megapascals) to press the polymer into thesilicone plate. The sample was cooled with a cold platen. A photographof the pressed sample is shown in FIG. 17. An optical digital photo at100× of a side view of the pressed sample shown in FIG. 18. An opticaldigital photo at 200× of the pressed sample shown in FIG. 19, wherethick and thin areas of the backing are apparent. Using an opticalmicroscope, the dimensions of the pressed sample were measured. Theposts were measured to be 700 micrometers high, and the polymer backingwas measured to be 90 micrometers thick.

Then the posts were capped using a household iron with wax paper. Theiron was set to “wool”. The wax paper was set on top of the stems to becapped. The iron was set on top of the wax paper and posts forapproximately 5 seconds.

Foreseeable modifications and alterations of this disclosure will beapparent to those skilled in the art without departing from the scopeand spirit of this invention. This invention should not be restricted tothe embodiments that are set forth in this application for illustrativepurposes.

What is claimed is:
 1. A mechanical fastening net comprising: apolymeric backing comprising first and second major surfaces, aplurality of openings in the polymeric backing extending between thefirst and second major surfaces, and upstanding posts on at least one ofthe first or second major surface of the polymeric backing, wherein fora portion of the polymeric backing between two adjacent openings nothaving upstanding posts abutting the two adjacent openings, thepolymeric backing has a minimum thickness where it abuts one of the twoadjacent openings that is smaller than a maximum thickness of thepolymeric backing at a location between the two adjacent openings. 2.The mechanical fastening net of claim 1, wherein the upstanding postsare on only the first major surface of the polymeric backing
 3. Themechanical fastening net of claim 1, wherein in at least some locationsof the polymeric backing between the openings, there is a plurality ofthe upstanding posts.
 4. The mechanical fastening net of claim 1,wherein for at least some locations of the polymeric backing between theopenings, the locations have a length and a width perpendicular to thethickness of the net, and wherein the length and width are both largerthan at least the bases of the upstanding posts.
 5. A laminatecomprising the mechanical fastening net of claim 1 joined to a carrier.6. The laminate of claim 5, wherein the mechanical fastening net isjoined to the carrier with adhesive, and wherein the adhesive is exposedin at least some of the openings.
 7. A method of making the mechanicalfastening net of claim 1, the method comprising: providing a netcomprising strands of polymer and open areas between the strands ofpolymer; and molding a portion of the polymer in the strands of the netinto upstanding posts to form the mechanical fastening net.
 8. Themethod of claim 7, wherein the strands are periodically bonded togetherat bond regions throughout the net, and wherein the strands do not crosseach other.
 9. The method of claim 7, wherein the strands of polymer aresolid.
 10. The method of claim 9, wherein molding comprises pressing thenet onto a heated mold surface with cavities having the inverse shape ofthe upstanding posts.
 11. The method of claim 7, wherein the strands ofpolymer are molten.
 12. A mechanical fastening net comprising: apolymeric backing comprising first and second major surfaces, aplurality of openings in the polymeric backing extending between thefirst and second major surfaces, and upstanding posts on at least one ofthe first or second major surface of the polymeric backing, wherein forat least some of the openings, each opening has a series of differentareas through the opening in a number of planes parallel to the first tosecond major surfaces ranging from a smaller, minimum area to a larger,maximum area, and wherein the smaller, minimum area is not at either theplane of the first major surface or the plane of the second majorsurface.
 13. The mechanical fastening net of claim 12, wherein in atleast some locations of the polymeric backing between the openings,there is a plurality of the upstanding posts.
 14. The mechanicalfastening net of claim 12, wherein for at least some locations of thepolymeric backing between the openings, the locations have a length anda width perpendicular to the thickness of the net, and wherein thelength and width are both larger than at least the bases of theupstanding posts.
 15. A laminate comprising the mechanical fastening netof claim 12 joined to a carrier, wherein the mechanical fastening net isjoined to the carrier with adhesive, and wherein the adhesive is exposedin at least some of the openings.
 16. A method of making the mechanicalfastening net of claim 12, the method comprising: extruding a netcomprising strands of polymer and open areas between the strands ofpolymer; and molding a portion of the polymer in the strands of the netinto upstanding posts to form the mechanical fastening net.
 17. Themethod of claim 16, wherein extruding the net comprises: providing anextrusion die comprising a plurality of shims positioned adjacent to oneanother, the shims together defining a cavity, the extrusion die havinga plurality of first dispensing orifices in fluid communication with thecavity and a plurality of second dispensing orifices in fluidcommunication with the cavity, such that the first and second dispensingorifices are alternated; and dispensing first polymeric strands from thefirst dispensing orifices at a first strand speed while simultaneouslydispensing second polymeric strands from the second dispensing orificesat a second strand speed, wherein the first strand speed is at least 2times the second strand speed to provide the net.
 18. The method ofclaim 16, wherein extruding the net comprises: providing an extrusiondie comprising a plurality of shims positioned adjacent to one another,the shims together defining a first cavity and a second cavity, theextrusion die having a plurality of first dispensing orifices in fluidcommunication with the first cavity and having a plurality of seconddispensing orifices connected to the second cavity, such that the firstand second dispensing orifices are alternated; and dispensing firstpolymeric strands from the first dispensing orifices at a first strandspeed while simultaneously dispensing second polymeric strands from thesecond dispensing orifices at a second strand speed, wherein the firststrand speed is at least 2 times the second strand speed to provide thenet.
 19. The method of claim 16, wherein molding a portion of thepolymer in the strands of the net into upstanding posts comprises:providing a net extrudate upon extruding the net; and feeding the netextrudate onto a continuously moving forming surface with cavitieshaving the inverse shape of the upstanding posts.
 20. The method ofclaim 19, wherein the continuously moving forming surface is a firstroll that forms a nip with a second roll.